First steps towards a practical application for magnetic skyrmions
Researchers at Johannes Gutenberg University Mainz (JGU) have succeeded in developing a key constituent of a novel unconventional computing concept. This constituent employs the same magnetic structures that are being researched in connection with storing electronic data on shift registers known as racetracks.
In this, researchers investigate so-called skyrmions, which are magnetic vortex-like structures, as potential bit units for data storage.
However, the recently announced new approach has a particular relevance to probabilistic computing. This is an alternative concept for electronic data processing where information is transferred in the form of probabilities rather than in the conventional binary form of 1 and 0. The number 2/3, for instance, could be expressed as a long sequence of 1 and 0 digits, with 2/3 being ones and 1/3 being zeros.
The key element lacking in this approach was a functioning bit reshuffler, i.e., a device that randomly rearranges a sequence of digits without changing the total number of 1s and 0s in the sequence. That is exactly what the skyrmions are intended to achieve. The results of this research have been published in the journal Nature Nanotechnology.
The researchers used thin magnetic metallic films for their investigations. These were examined in Mainz under a special microscope that made the magnetic alignments in the metallic films visible. The films have the special characteristic of being magnetized in vertical alignment to the film plane, which makes stabilization of the magnetic skyrmions possible in the first place.
Skyrmions can basically be imagined as small magnetic vortices, similar to hair whorls. These structures exhibit a so-called topological stabilization that protects them from collapsing too easily – as a hair whorl resists being easily straightened.
It is precisely this characteristic that makes skyrmions very promising when it comes to use in technical applications such as, in this particular case, information storage. The advantage is that the increased stability reduces the probability of unintentional data loss and ensures the overall quantity of bits is maintained.
Reshuffling for data sequence organization
The reshuffler receives a fixed number of input signals such as 1s and 0s and mixes these to create a sequence with the same total number of 1 and 0 digits, but in a randomly rearranged order. It is relatively easy to achieve the first objective of transferring the skyrmion data sequence to the device, because skyrmions can be moved easily with the help of an electric current.
However, the researchers working on the project now have for the first time managed to achieve thermal skyrmion diffusion in the reshuffler, thus making their exact movements completely unpredictable. It is this unpredictability, in turn, which made it possible to randomly rearrange the sequence of bits while not losing any of them. This newly developed constituent is the previously missing piece of the puzzle that now makes probabilistic computing a viable option.
Successful cross-discipline collaboration
"There were three aspects that contributed to our success. Firstly, we were able to produce a material in which skyrmions can move in response to thermal stimuli only. Secondly, we discovered that we can envisage skyrmions as particles that move in a fashion similar to pollen in a liquid. And ultimately, we were able to demonstrate that the reshuffler principle can be applied in experimental systems and used for probability calculations.
The research was undertaken in collaboration between various institutes and I am pleased I was able to contribute to the project," emphasized Dr. Jakub Zázvorka, lead author of the publication. Zázvorka conducted his research into skyrmion diffusion as a research associate in the team headed by Professor Mathias Kläui and is meanwhile working at Prague University.
"It is very interesting that our experiments were able to demonstrate that topological skyrmions are a suitable system for investigating not only problems relating to spintronics, but also to statistical physics. Thanks to the MAINZ Graduate School of Excellence, we were able to bring together different fields of physics here that so far usually work on their own, but that could clearly benefit from working together.
I am particularly looking forward to future collaboration in the field of spin structures with the Theoretical Physics teams at Mainz University that will feature our new TopDyn – Dynamics and Topology Center," emphasized Mathias Kläui, Professor at the Institute of Physics at JGU and Director of the Graduate School of Excellence Materials Science in Mainz (MAINZ).
"We can see from this work that the field of spintronics offers interesting new hardware possibilities with regard to algorithmic intelligence, an emerging phenomenon also being investigated at the recently founded JGU Emergent Algorithmic Intelligence Center," added Dr. Karin Everschor-Sitte, a member of the research center's steering committee and head of the Emmy Noether research group TWIST at the JGU Institute of Physics.
The reshuffler basically works as a skyrmion blender: a specific initial sequence is entered and the result is a randomly reshuffled sequence of output states.
ill./©: Andreas Donges, University of Konstanz
Professor Dr. Mathias Kläui
Condensed Matter Theory Group
Institute of Physics
Johannes Gutenberg University Mainz
55099 Mainz, GERMANY
phone +49 6131 39-23633
Graduate School of Excellence Materials Science in Mainz (MAINZ)
Johannes Gutenberg University Mainz
55099 Mainz, GERMANY
phone +49 6131 39-26984
fax +49 6131 39-26983
J. Zázvorka et al., Thermal skyrmion diffusion used in a reshuffler device, Nature Nanotechnology, 22 April 2019,
https://emergent-ai.uni-mainz.de/ – Emergent Algorithmic Intelligence Center at JGU ;
http://www.uni-mainz.de/presse/20661_ENG_HTML.php – "Investigations of the skyrmion Hall effect reveal surprising results" (27 Dec. 2016)
http://www.uni-mainz.de/presse/20165_ENG_HTML.php – "International research team achieves controlled movement of skyrmions" (7 March 2016)
http://www.uni-mainz.de/presse/18027_ENG_HTML.php – "Physicists observe motion of tiny magnetic whirls" (3 Feb. 2015)
Petra Giegerich | idw - Informationsdienst Wissenschaft
Marine Skin dives deeper for better monitoring
23.04.2019 | King Abdullah University of Science & Technology (KAUST)
CubeSats prove their worth for scientific missions
17.04.2019 | American Physical Society
An international collaboration with participation of the University of Bern has demonstrated for the first time in an interference experiment that antimatter particles also behave as waves besides having particle properties. This success paves the way to a new field of investigations of antimatter.
Matter waves constitute a crucial feature of quantum mechanics, where particles have wave properties in addition to particle characteristics. This...
A photodetector converts light into an electrical signal, causing the light to be lost. Researchers led by Tracy Northup at the University of Innsbruck have now built a quantum sensor that can measure light particles non-destructively. It can be used to further investigate the quantum properties of light.
Physicist Tracy Northup is currently researching the development of quantum internet at the University of Innsbruck. The American citizen builds interfaces...
It is only an inconspicuous piece of paper, but it is an important milestone for autonomous driving: At the end of 2018 the three partners from the joint research project RadarGlass applied for a patent for an innovative radar system. The Fraunhofer Institute for Laser Technology ILT from Aachen, the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP from Dresden and the Institute of High Frequency Technology IHF of RWTH Aachen University have developed a coating process chain that enables radar sensors to be integrated in car headlights. After almost two years in development they have manufactured a working prototype.
Completely autonomous vehicles pose an enormous challenge for sensor technology because, in principle, the supporting system must hear, see and feel better...
Physics and Chemistry scholars from Hong Kong Baptist University (HKBU) have invented a new method which could speed up the drug discovery process and lead to the production of higher quality medicinal drugs which are purer and have no side effects. The technique, which is a world-first breakthrough, uses a specific nanomaterial layer to detect the target molecules in pharmaceuticals and pesticides in just five minutes.
The new HKBU invention can be applied to the drug discovery process, as well as the production and quality control stages of pharmaceutical manufacturing. It...
The use of potassium bromide in the production of graphene on a copper surface can lead to better results. When potassium bromide molecules arrange themselves between graphene and copper, it results in electronic decoupling. This alters the electrical properties of the graphene produced, bringing them closer to pure graphene, as reported by physicists from the universities of Basel, Modena and Munich in the journal ACS Nano.
Graphene consists of a layer of carbon atoms just one atom in thickness in a honeycomb pattern and is the subject of intensive worldwide research.
29.04.2019 | Event News
17.04.2019 | Event News
15.04.2019 | Event News
06.05.2019 | Life Sciences
06.05.2019 | Life Sciences
06.05.2019 | Health and Medicine